Milenge Kamalebo and De Kesel Journal of Ethnobiology and Ethnomedicine (2020) 16:8 https://doi.org/10.1186/s13002-020-0357-5 RESEARCH Open Access Wild edible ectomycorrhizal fungi: an underutilized food resource from the rainforests of Tshopo province (Democratic Republic of the Congo) Héritier Milenge Kamalebo1,2* and André De Kesel3 Abstract Background: Ectomycorrhizal (EcM) fungi constitute a source of income as well as proper food with considerable nutritional value. Although edible EcM fungi are highly diverse and expected to host considerable nutritional attributes, only few studies focus on their use and promotion in the province of Tshopo (DR Congo). This study provides original ethnomycological and diversity data on edible ectomycorrhizal rainforest fungi from the Man-and- Biosphere reserve of Yangambi and the reserve of Yoko. Methods: The list of edible fungi follows the current taxonomy. Taxa were collected in plots situated in different types of rainforests. Each taxon is supported by herbarium reference specimens. Ethnomycological data on locally consumed EcM fungi were collected from randomly selected people living near the Man-and-Biosphere reserve of Yangambi and the Yoko reserve. People were interviewed using a semi-structured questionnaire. The interview campaign involved 160 informants, all randomly selected from 6 different ethnic communities. Results: The results reveal that rainforests from the Yangambi Biosphere reserve and Yoko forest reserve provide a relatively high number of edible fungi, more than local people actually use. Mixed forest stands hold the highest diversity in saprotrophic edible fungi (p value < 0.001) while no significant difference (p value > 0.05) was observed in the number of saprotrophic and EcM fungi within monodominant forests. In spite of being accessible, this renewable natural resource is underexploited. Although a wide array of EcM fungi is available in primary forests dominated by ectomycorrhizal trees, local people’s major interest goes to the saprotrophic fungi from areas with degraded mixed forests. Conclusion: The lack of local interest for EcM fungi is probably related to the considerable distance people have to cover to collect them. As a result, the edible EcM fungi from the Tshopo area represent a potentially interesting but underutilized resource. Keywords: Edible ectomycorrhizal fungi, Fungal consumption, Tshopo, Democratic Republic of the Congo * Correspondence: [email protected] 1Faculté des Sciences, Université de Kisangani, BP 2012, Kisangani, Democratic Republic of the Congo 2Centre de Recherches Universitaires du Kivu (CERUKI-ISP), BP 854, Bukavu, Democratic Republic of the Congo Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Milenge Kamalebo and De Kesel Journal of Ethnobiology and Ethnomedicine (2020) 16:8 Page 2 of 13 Introduction Tshopo is mainly characterized by a tropical evergreen In many regions of the world, including tropical Africa, rainforest and some groves of semi-deciduous forests edible fungi often constitute a source of income and food, found on hills and plateaus [20–22]. These rainforests with a non-negligible nutritional value [1–6]. According are mainly dominated by species such as Gilbertioden- to De Kesel et al. [4] and Degreef et al. [7], documenting dron dewevrei (De Wild.) J. Léonard, Brachystegia laur- the relative importance and potential of locally used EcM entii (De Wild.) Louis, Scorodophloeus zenkeri Harms, fungi remains vital for improving strategies for their con- Prioria balsamifera (Vermoesen) Breteler, and Julbernar- servation and promoting sustainable use. Edible EcM dia seretii (De Wild.) Troupin [20–24]. fungi provide high-quality and important amount of crude The fungi were collected between 2013 and 2016, protein, minerals and carbohydrates, fats, etc. [2, 3, 5, 6]. mostly within plots situated in the rainforests of the Bio- The amount of fungal crude protein for instance is gener- sphere reserve of Yangambi (0° 51′ 01.62″ N; 24° 31′ ally ranked between 19 and 35% of the dry mass [2]. Fur- 43.53″ E) and Yoko reserve (0° 17′ 34.9″ N; 25° 18′ thermore, many species of edible EcM fungi provide 27.4″ E) (Fig. 1). Monitoring of plots follows Lodge et al. higher amount of unsaturated fatty acids than saturated [25], and fungal sampling was performed within forests ones [2, 5]. Unlike saturated fatty acids (found in high dominated by Gilbertiodendron dewevrei, Brachystegia amount in animal fats), unsaturated fatty acids are sug- laurentii, Julbernardia seretii, Uapaca heudelotii, and gested to be essential in the human diet [2]. The high pro- Uapaca guineensis and in mixed forests. Three plots of portion of unsaturated fatty acids and high percentage of 100 × 100 m were demarcated in each type of forest; linoleic acid found in edible EcM mushrooms lead to con- each of them divided in a 20 × 20 m grid. Due to the sider them as a healthy food [2]. In addition, the proteins elongated shape of Uapaca heudelotii-dominated forests, of most of edible EcM taxa contain all nine essential more stretched plots were installed in this forest type. In amino acids (leucine, isoleucine, valine, tryptophan, lysine, each plot, the aboveground fruiting bodies of all EcM threonine, phenylalanine, methionine, and histidine) used fungi were collected by walking parallel bands covering in humans’ nutrition [2, 5]. the entire plot [26]. Unidentifiable fruit bodies were EcM fungi constitute one of the most important photographed in situ and dried after notes were taken groups of edible fungi worldwide. In tropical Africa, from their macromorphological features (following [18]). EcM fungi are massively consumed in the Zambezian re- Voucher specimens were dried using a field drier [27] gion [4, 5, 8–14], and in the savanna woodlands and and deposited at the herbarium of Meise Botanic Garden open forest areas of the Soudanian region [15–17]. (Belgium). Within the Zambezian geographical zone, local people collect, sell, and consume impressive quantities of EcM Fungal identification taxa. The socio-economic interest for EcM fungi is con- The identification of voucher specimens was done using sidered a major incentive for obtaining strong and macroscopic and microscopic characteristics, as outlined in broadly supported forest conservation programs [4]. Eyi-Ndong et al. [18]. The available taxonomic literature only Within the rainforests of Tshopo province (Demo- covers a fraction of the Central African rainforest fungi. The cratic Republic of the Congo), many species of edible following contributions were used for identification: Heine- EcM fungi are available. In this area, EcM fungi are typ- mann [28], Heim [29], Pegler [30], Heinemann and Ramme- ically found within primary forests dominated by EcM loo [31–33], Buyck [8, 34, 35],DeKeseletal.[4, 9, 16], partner trees such as Gilbertiodendron dewevrei (De Verbeken and Walleyn [36], Eyi-Ndong et al. [18], as well as Wild.) J. Léonard, Brachystegia laurentii (De Wild.) identification keys provided by the Fungus Flora of Tropical Louis, Julbernardia seretii (De Wild.) Troupin, Uapaca Africa (https://www.ffta-online.org/) and Edible Fungi of guineensis Müll. Arg, and U. heudelotii Baillon [18, 19]. Tropical Africa (https://www.efta-online.org/). Species names This study aims to assess the distribution and diversity and author’s abbreviations largely follow Index Fungorum of edible fungi within various types of rainforests found (http://www.indexfungorum.org/Names/Names.asp). Uniden- in the Man-and-Biosphere reserve of Yangambi and the tified taxa were left out of the analysis. Yoko reserve. We show how access and availability, as well as trophic level of fungi, affect the interest of local Ethnomycological data acquisition and treatment people, and how this in turn creates or annihilates op- Ethnomycological data on locally consumed fungi were col- portunities for forest conservation. lected from local people living around the Man-and- Biosphere reserve of Yangambi and the Yoko reserve. Data Materials and methods were collected using open, semi-structured interviews (paper Study site and sampling of fungi fill-in questionnaires). The interviews involved mainly the Fieldwork was done in the province of Tshopo, located head of the family, sometimes assisted by other family mem- 2° N 2° S and 22° E 28° E [20]. The vegetation from bers. The questions focused basically on the informant’s Milenge Kamalebo and De Kesel Journal of Ethnobiology and Ethnomedicine (2020) 16:8 Page 3 of 13 Fig. 1 Location of the study area knowledge concerning the different locally consumed edible 600 ≈ 1þðNÂ0:072Þ 152, households that were fitted to 160 infor- fungi. Interviews were obtained from 160 informants, all ran- mants. Referring to the mean distribution of households per domly selected, but belonging to one of 6 ethnic communi- sampling site (villages and suburbs of Yangambi), 7 house- ties